I've found that if I buy the individually wrapped chocolates it's much easier to eat just one. When I bought a whole candy bar it was way too easy to eat the whole thing. I also only eat them as a reward, or during PMS or high stress times. Just like I did when I ate the sugary ones, I tell myself that another one will taste just the same, so why bother? It's not a fool-proof plan, but it helps.
I brought a couple with me to my office party last night. It sure helped when I saw the dessert table. OMG-they really went overboard with that one, I'm sure I would have had a bite if I didn't have my little sweets in my purse!